Two new theories try to explain how the crescent-shaped sand mountains persist

By Erin Wayman, 16:49 PM August 22, 2013

No sand dune is an island.

Interactions between crescent-shaped, or barchan, dunes stabilize the mounds and explain how vast swarms of them can persist over time, two new studies find. But the studies don’t agree on what kind of interactions matter: One team argues that dunes colliding and breaking apart keeps barchan fields from growing into giant sand piles, while the other claims that dunes calving off each other are the key.